Manufacture of electric detonators, percussion caps, and like articles



April 18, 1933. D. T. JONES ET AL 0 MANUFACTURE OF ELECTRIC DETONATORS, PERCUSSION CAPS, AND LIKE ARTICLES Filed Jan. 50, 1929 "0 Times 9 9 1 rmWQ v a 22 2 I A; Wi

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Patented Apr. 18, 1933;

PATEN err-ice rev-m TBEOR JoNEs AND FREDERICK JosEPn- MoonE; OF SAL'I'COATS, SCOTLAND.

ASSIGNORS TO I. DU PONT DE NEMOURS AND C 01 WILMINGTON, DELAWARE,

A. CORPORATION OF DELAWARE MANUFACTURE or ELECTRIC nEro mrons, PERCUSSION cars, m mmanrroms Application filed January 30, 1929, Serial 'No. 386,216, and in fireat Britain ,l?ebruary 2, 1928.

This invention relates to electric detonators, electric fuses and fuse heads which are I a material itself mixed with a suitable ingredient to render it conducting, and also relates to percussion caps' and the like, for example friction primers for electrical firing.

The object of the invention is to provide improved or modified electric detonators, percussion caps and the like. As a result of researches, We havefound that the lead salts of 2-mon0-nitro-resorcin are of considerable utility in connection with electric detonators and electric percussion-caps and the like, as referred to. above, particularly in the latter case, as they are sensitive to percussion and friction to such a degree as to render them useful components in percussion caps and like percussion and friction primers, especially when they are prepared on certain lines.

i The invention in brief consists in electric detonators, electric fuses and fuse heads as described above in which the igniting material is formed from or includes one or more lead salts of 2-mono-nitroresorcin', of which special cases are the basic, normal and acid salts. 4

The invention also consists in percussion caps and like percussion or friction primers containing one or more of the lead saltsof 2-mono-nitro-resorcin of which special cases are the basic normal .and acid salts.

The invention also consists in the improvements in the manufacture of electric detonators, percussionlcap's and the like, substantially as hereinafter described.

Referringto the accompanying drawing, which illustrates methods of carrying the invention into efi'ect:

Figure 1 is a sectional elevation of a low tension fuse head;

Figure 2 is a sectional elevation of a high:

tension fuse head;

Figure 3 is a sectional elevation of an electric fuse or lgnlter; and

Figure 4 is a sectlonal elevation of a moditflied form of electric fuse of the high tension ype.

Referring to Figure 1, the low tension fuse head illustrated consists essentially of a piece of an insulating material 1 such as cardboard with a stepped end coated on both sides with a thin layer of metallic foil 2. A thin wire 3 is attached across the step, thus forming a bridge. The bridge is then covered with a readily inflammable material 4. l Referring to Figure 2, the high tension fuse head illustrated consists essentially of a piece of insulating material'l such as cardboard with an unstepped end and coated on both sides with a thin layer of metallic foil 2. I The lower end is then coated with a readily inflammable material 4 to which a conducting ingredient has been added.

Leading wires 5, 6, are then attachedto the free ends of the metallicfoil. Such an arrangement may be fixed in a paper tube, in-

sorted into an ordinary detonator and secured therein by crimping or .by cementing.

On allowing an electric current to flow by way of the leading wires through the bridge mass of insulating material 1, such as sulphur, wood, bitumen or rubber through which insulated conductingwires 2, 3, are fixed so that the bared ends protrude. A piece of bridge wire 4 is attached to the'bared ends. The drawing shows the attachment carried out by means of solder 5, 5. The bridge wire is then embedded in the igniting material, which may be fixed to the bridge wire in a suitable manner, or be retained in a suitable container.

Referring to Figure 4, high tension electric fuses or igniters aremade by omitting the bridge wire and embedding the ends of the conducting wires into the conducting material. The conducting material may be coated around the bared ends of the conducting wires, or retained in a suitable container.

The following examples illustrate how suitable lead salts of 2-mono-nitro-resorcin 100 wire, or the conducting mixture, the fuse.

may be conveniently prepared for use according to the present invention Ewample 1 This is an example of a method of prepar ing a lead salt of 2-mono-nitro-resorein, particularly for use in connection with electric- 1.5 gram molecule of sodium hydroxide is added a slight excess of lead acetate solution.

Samples precipitated at from 35 to give better firing results than those. precipitated at lower temperatures. This example is not limited to the proportions given, for example, 0.5 gramme molecule of sodium hydroxide may be used in place of 1.5 gramme molecule mentioned in the above example. Soluble salts of lead other than the acetate may also be used. The analysis of the basic lead salt prepared as described above shows a lead content of 68.9 per cent. The formula is therefore probably C H O NPb2. By varying, however, the proportion of sodium hydroxide and the conditions of precipitation, a basic salt may be obtained with a lead content of 71 per cent. apparently corresponding to a dehydrated form of the foregoing, and substantially the same in its behaviour.

' Example 2 Referring particularly to electric detonators and the like, in place of the basic lead salt of 2-mono-nitroresorcin there may be employed the normal lead salt or the acid lead salt or both) of 2-mono-nitroresorcin. This normal lead salt of 2-mono-nitroresorcin containing 57.5 per cent. lead-may be prepared from the previously known 2-mononitroresorcin by the addition of a solution of lead nitrate to a solution of the sodium salt of mono-nitroresorcin, the salts being in equivalent proportions to give the normal salt: C H O N.Pb.

Emample 3 Referring again particularly to electric detonators and the like, according to this example the acid lead salt of 2-mono-nitroresorcin is employed. The acid lead salt of 2-mono-nitroresorcin containing 40.2 per cent. lead may be prepared from 2-mononitroresorcin by the addition of a solution of lead nitrate containing acetic acid to sodium mono-nitroresorcinate, the salts being in equivalent proportions to give the acid salt:

' there is atendency to' scatter the outer dips iz s sNa Ewample 4 Referring particularly to percussion caps and the like, this illustrates a condenient method for manufacturing a suitable lead salt of 2-mono-nitroresorcin.

According to this example, a solution of 10 parts of 2-mono-nitrpiresorcin in the exact amount of sodium hy roxide to give the disodium salt and diluted to a volume of 500 parts is run into a solution of 22 parts of lead nitrate in 500 parts water, kept at 33-35 C. in a water bath during thirty minutes. After cooling, the preci itate which is bulky can be readily filtered 0 washed with warm water, acetone and dried.

' Ewamplefi C. The precipitate in this case settles rap idly, and is much denserthan in Example 4.

r Ezvample 6' Referring again more particularly topercussion caps and the like, this is an example of four difi'erent cap mixtures by way of illustration 7 Per cent (a) Lead mono-nitroresorcinate 35 (of about 64% lead) I Lead styphnate .i.. 30 Barium nitrate 35 (6) Lead styphnate; 33% Lead mono-nitroresorcinate- 33 1 .(of about 57% lead) Pentaerythritol, tetranitrate 33 (0)'Lead mononitroresorcinate 60 (containing 64% lead) Lead styphnate 40 (01) Potassium picrate 20 Barium nitrate 30 Lead mono-nitroresorcinate 50 (containing 64% lead) General The normal and acid lead salts of lead mono-nitroresorcinate separately ortogether with the basic salt, or with lead oxide, or with hydrated lead oxide, or with one another.

Particularly in the case of electric detonators and the like, the following points may be noted (a) The new salts are not such powerful explosives as basic lead trinitroresorcinate. When a fuse head is ignited and the material of the flashing composition is too powerful,

of thefuse head instead of igniting them. The ignition of the lead salts of g-mononitroresorcin is gentle, and ignites the outer resorcin.

quietly. They are therefore safer for handling than leadtrinitroresorcinate.

(0) They form a readily workable and permanent paste with the ordinary collodion used for dips in the fuse head manufacture. This paste is formed without gelatin.

(d) They stand extreme climatic storage conditions without deterioration. v

Particularly in the case of percussioncaps and the like, it is noted that the products of Examples 4 and 5, after drying, run well, and presumably consist wholly or in part of the normal lead salt of 2-mono-nitroresorcin.

' Basic and acidic salts for use in connection with percussion caps and the like may conveniently be prepared as described above.

Any of the forms of lead salts of 2-mononitroresorcin may be used as the sole ingredients of percussion caps and like percussion anddfriction primers or admixed salts may be use The invention is not limited to the methods of makingthese salts referred to above, nor

to the compositions or proportions of'these salts and other ingredients in percussion caps .and like percussion and friction primers given above, but for example ingredients heretofore used in cap manufacture may be employed.

We claim 1. Electric detonators, electric fuses, ig-

niters and fuseheads in which the igniting material includes lead salts of 2-mono-nitroresorcin of which special cases are the basic, normal and acid salts.

2. Electric detonators, electric fuses, igniters and fuseheads as claimed in claim 1, in which a basic lead salt of2-m0no-nitroresorcin constitutes the igniting material, this salt being obtained as a precipitate from a mixture of alkali salt of 2-mono-nitroresorcin anda soluble lead salt.

3. Electric detonators, electric fuses, igniters and fuseheads as claimed in claim 1 7. Electric detonators, fuses, igniters and fuseheads, in which the ignition material consists of acid lead salts of 2-mono-nitroresorcin." a

8. Electric detonators, fuses, igniters and fuseheads, in which the ignition material consistsof normal lead salts of 2-mono-nitroresorcin.

9. Electric detonators, fuses, igniters and fuseheads, in which the ignition material consists of basic lead salts of 2-mono-nitroresorcin. 1

10. Electric detonators, fuses, igniters and fuseheads in which the priming material consists of acid lead salts of 2-mono-nitrores-' in which normal lead salt of 2-mono-nitroresorcin constitutes the igniting material, this salt being obtained as a precipitate from an admixture of a solution of .lead nitrate and a solution ,of an alkali salt of mono-nitro- 4. Electric detonators, eTectric which an acid lead salt of 2-mono-nitroresorcin is used, this salt being obtained as a preclpitate from an admixture of an alkali salt of mono-nitroresor'cin with a solution of lea nitrate containing acetic acid. 5. Percussion caps and percussion and friction primers containing a lead salt of 2-mononitroresorcin.

fuses, i nlters and fuseheads as clalmed in claim 1 1n 6. Percussion caps and percussion and fric- 'tion primers containing 'a mixture of lead salts of 2-mono-nitroresorcin', these being selectedfrom a group consisting of basic, normal and acid salts. 

